To introduce fragmented solid fuel into a vessel, particularly when the vessel must be kept under pressure, it has already been proposed to use a screw conveyor constituted by one or several screws rotated inside a sleeve provided at its upstream end with an orifice for the intake of the material and at its downstream end with at least one die opening through an outlet orifice inside the vessel and in which a slab or roll of compressed material is formed by extrusion. In this way, the solid fuel can be introduced continuously into the vessel while maintaining the fluid-tightness of the latter due to the compression of the material obtained in the die.
As a result, particularly when the vessel is under considerable pressure, the roll introduced is very compact and it is necessary to disintegrate it to carry out the combustion or gasification thereof. To this end, it is possible to use a gas jet injected under high pressure on to the roll emerging from the die. However, because the roll is very compact, it is not certain, with such a method, that true pulverization of the fuel can be effected, the roll being breakable into lumps of a certain size.
On the other hand, by this method one is led, to ensure the disintegration of the roll, to inject into the vessel a considerable delivery rate of gas risking reduction in the energy yield of combustion or of the gasification of the fuel.
It is an object of the invention to provide a method and device enabling these drawbacks to be remedied while ensuring, even for relatively low gas flow rate, perfect pulverization of the fuel introduced.